The ATi3.7-4.2 from Narda-ATM is a RF & Microwave Isolator with Frequency 3.7 to 4.2 GHz, Average Power 2 W, Average Power Forward 2 W, Peak Power Forward 0.02 kW, Insertion Loss 0.1 to 0.15 dB. Tags: Module with Connector, Coaxial Isolator. More details for ATi3.7-4.2 can be seen below.